Stretch-bending machine with work clamps mounted on pivoted arms



Jul 18, 1950 Filed Dec. 2, 1944 E. A. RAT STRETCH-BENDING MACH HGEN2,515,734

INE WITH WORK CLAMPS MOUNTED ON PIVOTED ARMS 5 Sheets-Sheet l INVENTOREWALT A RATHGEN BY FM ATTORNEY July 18, 1950 CLAMPS MOUNTED ON PIVOTEDARMS 5 Sheets-Shget 2 Filed Dec. 2, 1944 IIIIIII N UFW INVENTOR A TTORNEY N E a w A A m m July 18, 1950 Filed Dec. 2, 1944 FIG? ' E. A. RATHGENSTRETCH-BENDING MACHINE WITH WORK CLAMPS MOUNTED ON PIVOTED ARMS 5Sheets-Sheet 3 iOi iNl ENTOR I I EWALT A. RATHGEN ATTORNEY E. A. RATHGENSTRETCH-BENDING MACHINE WITH WORK CLAMPS MOUNTED ON PIVOTED ARMS July18, 1950 5 Sheets-Sheet 4 Filed Dec. 2, 1944 FIG. 12

INVENTOR ATTORNEY July 18, 1950 E. A. RATHGEN 2,515,734

STRETCH-BENDING MACHINE WITH WORK CLAMPS MOUNTED 0N PIVOTED ARMS FiledDec. 2, 1944 s Sheets-Sheet 5 FIGJO INVENTOR EWALT A. RATHGEN A TTORNE Yprovided in the top plate 44 of the arm 31. The rod 54 of the piston 55in the cylinder has its outer end secured to a bracket 56 which isslidably guided by the top plate 44. Attached to the bracket 56 byuniversal joint connecting means 51 is a vise 58 adapted for holding oneend of a workpiece 59.

Secured to the base 20 between the inner ends of the arms 31 is asupport 60 for a table 6|. The table has a raised margin 62 which incombination with the top surface of the table serves for holding aforming die 63. The die has one of its margins shaped in accordance withthe form and the cross section of the workpiece 59, which in theembodiment is shown as an angle section.

Pressure medium may be admitted to the cylinders 29 and 5| by means ofvalves 64 and 65 and pipe lines 66, 61 and 68, 69. The pressure mediumis supplied by a source (not shown) which feeds into the pipes 10, 1|leading to the valves 94, 65. 1| are the exhaust or return pipes for thepressure medium.

The control means 50, 64, 65 are for the sake of simple diagrammaticillustration shown near the respective appertaining motors and cylindersbut they will be arranged in reality, as a matter of course, together inone or. two groups at a location or locations most suitable for theperson or persons handling the production.

The operation of the machine will be evident to those skilled in the artfrom the foregoing description of the elements of the machine, so that abrief description of the operation will suflice.

After the die 63 has been placed on top of the table BI and thecylinders 5| have been secured in place on the arms 31 at the distancefrom each other corresponding to the length of the workpiece, the latteris firmly secured in the Vises 58. Hereafter pressure medium is admittedto the inner ends of the cylinders 5| by means of the valves 65 andpipes 68 so that the workpiece 59 is subjected to stretching. While theworkpiece is in the stretched condition, the arms 31 are swung abouttheir pivots 34 by means of the motors 45, the gears 41, the pinions 48and the gear sectors 39, so that the workpiece is wrapped around theworking edge of the die 53. During the movement of the arms. pressure inthe cylinders 5| is maintained and, if need be, ressure medium admittedor partly released so as to maintain the desired stretching force whichwill cause the workpiece to assume permanently the exact form of the diesurface yet without being stretched beyond its breaking point.

For other forms of the die different positions of the journals 3 for thearms are required. such different positions can be easily attained bymoving the brackets 30 along their ibs on the plate 2A after looseningthe bolts 4| as described hereinbefore.

If the form of the die is not symmetric relato be moved verticallyrelative to the die and its support. This vertical movement is achievedby moving the plate 24 with the arms 31 and all other accessories, suchas the Vises 58, the cylinders 5|, the motors 46, the gears 41 and thegear segments 39, vertically on the plate 22 by admitting pressuremedium to the lower part of the cylinder 29 while the arms aresimultaneously swung about their pivots by means of the motors 45.

. The embodiment illustrated in Figures 7 to 14 differs from the firstembodiment mainly in the means for swinging the arms about their pivotsand in the means for moving the die and the Vises relative to each otherin vertical direction. This second embodiment shows certain detailswhich maybe incorporated also in the first embodiment, such as means forconveniently adjusting the position of the pivots for the arms, and suchas a different type of universal joint connection between each vise andits piston rod.

The machine illustrated in Figures 7 to 14 has a large foundation platecarrying at one end a cross member 8|, at the other end a supportingstructure 82 and near its middle a pedestal or bracket 83.

The structure 82 has a base plate 84, the inner end of which carries acolumnar structure 85. Supported at a distance above the plate 84 bymeans of the columnar structure 85 is a horizontal beam structurecomposed of a lower plate 86 and an upper plate 81, vertical plates 88,89, 90 and intervening horizontal plates 9|, 92. The columnar structureis reinforced by an inclined member 93 extending between the plate 81and. the outer end of the plate 84. The entire structure 92 is composed,as will be evident from the drawing, of closed box sectional beams whichgive great strength and rigidity.

Gibs 94'are secured to the inner faces of the plates 89 and 90 and formwith the latter a horizontal guide and support for a pair of brackets95. A nut 95 secured to the bracket 95 is in engagement with a screwthreaded shaft 91 rotatably but axially immovably supported in thestructure 82 between the walls 9|, 92. One nut 96 and one shaft 91 areprovided on either side of the middle line (coincidingwith section lineIii-I0 in Figure 8) of the machine for each of the brackets 95. One endof each shaft 91 projects beyond the outer end of the structure 82andchas a head 99 adapted for turning the shaft by means of a wrench,crank or the like.

Pivoted to each bracket 95 by means of a vertical pin I90 is theinnerend of an arm IOI. A gear segment I02 is secured by flanges andbolts or rivets I03 to the arm IOI near the lower edge thereof. The gearsegment I02 has its periphery concentric to the respective pivot I00.The teeth ofthe gear segment I02 are engaged by a straight gearrack-I04. The segment I02 and the rack I04 are held in engagement by ashoe I05 which has flanges I06 engaging a pathway concentric to theouter periphery of and provided on the segment I02. Each rack I04 ishitched by a coupling I01 to the rod I08 of a piston I09. The piston I09is movable in a long cylinder II 0 which has its outer end journalled atI II to the cross beam 8|. There is, of course, one cylinder, piston,piston rod, rack and gear segment for each of the two arms IOI as isshown in Figure 7.

Pressure medium can be admitted to or released from the interior of thecylinders II0 on either side of the piston I09 by the valves I I2 andpipe lines H3, H4. Here again as in the first embodiment, the source ofpressure medium is I.) not shown but only the supply and exhaust or re-5. turn lines H5, H. It should be noted that the movement of each armis'independently controllable by its valve I I2.

The construction of the outer ends of the arms and of their top side issubstantially the same as in the first embodiment; this goes also forthe cylinders II6 for moving the Vises Ill and the valves (not shown)for controlling the admittance of pressure medium to the cylinderindependently from each other.

The universal joint connection between the piston rods I I 8 and theVises II I is slightly different from the first embodiment. A bracket II9 -is slidably guided on the top of each arm I 0|;

this bracket carries by means of a ring I20 and intersecting verticaland horizontal pivots I2I, I22 the inner end of the vise III.

Secured to the central portion of the structure 82 between the brackets95 is a member I23 which has formed therein an undercut vertical grooveI24. Slidably guided in this groove I24 by a correspondingly shapedextension I 25 is a member or structure I26. The opposite vertical edgeI2'I of this member is guided in a groove I20 provided on the previouslymentioned bracket 83.

The structure I 26 is in the form of a frame, the upper side of which isadapted for the attachment of a die or of a supporting table I29 bymeans of bolts extending'into screw threaded holes I30. The table andits support are held in appropriate alignment by a ridge formed on theunderside of the table entering a correspondingly shaped groove I29 onthe top of the structure I26.

Secured to the underside of the top member and arranged within theopening surrounded by the four sides of the structure I26 is a hydrauliccylinder I33. The rod I 34 of the piston in the cylinder I33 extendsthrough an aperture in the bottom member of structure I26 and has itsend secured to the foundation plate 80. Pressure medium may be admittedto the cylinder by means of the valve I35 from the pressure mediumsupply line I36 through the pipe line I31, I38; I39 is the return orexhaust pipe.

The operation of the machine shown in Figures 7 to 14 is substantiallythe same as that of the machine shown in Figures 1 to 6. After properadjustment of the pivots I00 by moving the brackets 95 along the crosshead of the structure 62, the adjustment of the cylinders I I 6 alongtheir arms NH and after having secured a die, such as indicated at I40,on the table I29, a workpiece indicated at MI is secured in the vises III. Hereafter pressure medium is admitted to the inner ends of thecylinders H6 and to the inner ends of the cylinders I I9 with the efiectthat the workpiece is stretched and simultaneously the arms I'EII withthe workpiece are swung about their pivots I00. If the workpiece iscurved in more than one plane, the die is moved relative to the visesholding the ends of the workpiece and relative to the machine as a wholein vertical direction by admitting pressure medium to the cylinder I33so that the structure I26 with the table I 29 and the die I49 is movedin vertical direction.

It will be understood that the invention is not restricted to thedetails of the two embodiments illustrated in the drawing anddescribedhere- 6 inbefore but that the invention is subject to suchmodifications and adaptations which are covered by the spirit and thelanguage of the attached claims.

What is claimed is:

1. A stretch-"bender comprising a base, a structure slidably guided onsaid base and provided with means for moving the structure back andforth, a pair of brackets supported by said structure slidably in adirection transversely to the direction of movement of said structure,said brackets each carrying an arm swingably about an axis which isabout parallel to the axis of rotation of the other arm and aboutparallel to the direction of movement of said structure, means on saidarms for gripping spaced portions of a workpiece and for stretching thelatter between them, a forming die supported on said base, and poweroperated means for swinging said arms about their respective axes intorelative positions in which a workpiece supported in stretched conditionbetween them is brought against said forming die.

2. A stretch-bender comprising a base, a structure guided on said basefor back and forth movement in one direction and means for impartingsuch movement to the structure, a pair of brackets supported by saidstructure slidably in a direction transversely to the direction ofmovement of the structure itself, said brackets each carrying an armswingably about an axis which is about parallel to the direction ofmovement of said structure, means on said arms for gripping spacedportions of the workpiece and for stretching the latter between them, aforming die supported in stationary condition on said base in a positionintersecting the line joining said gripping devices as said arms areswung about their respective axes.

EWALT A. RATHGEN.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 537,550 Schacht Apr. 16, 1895818,932 Baxter Apr. 24, 1906 957,200 Gail May 10, 1910 1,066,247 BrownJuly 1, 1913 1,264,248 Yoder Apr. 30, 1918 1,379,858 Gail May 31, 19211,462,315 Akey et a1 July 17, 1923 1,710,261 Kellogg Apr. 23, 19291,968,010 Bailey July 31, 1934 2,155,160 Bruno Apr. 18, 1939 2,190,423Henricson Feb. 13, 1940 2,292,731 Amiot Aug. 11, 1942 2,305,850 DrysdaleDec, 22, 1942 2,357,027 Seifried Aug. 29,1944 2,370,329 Seifried Feb.27, 1945 2,431,173 Hawkes Nov. 18, 1947 2,446,089 Hochreiter July 27,1948 FOREIGN PATENTS Number Country Date 482,769 Great Britain Apr. 5,1938

